/*
 * SonarQube
 * Copyright (C) 2009-2017 SonarSource SA
 * mailto:info AT sonarsource DOT com
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 3 of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 */
package org.sonar.process;

import javax.annotation.Nullable;
import java.util.HashMap;
import java.util.Locale;
import java.util.Map;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

/**
 * @since 3.0
 */
public final class Encryption {

  private static final String BASE64_ALGORITHM = "b64";

  private static final String AES_ALGORITHM = "aes";
  private final AesCipher aesCipher;

  private final Map<String, Cipher> ciphers = new HashMap<>();
  private static final Pattern ENCRYPTED_PATTERN = Pattern.compile("\\{(.*?)\\}(.*)");

  public Encryption(@Nullable String pathToSecretKey) {
    aesCipher = new AesCipher(pathToSecretKey);
    ciphers.put(BASE64_ALGORITHM, new Base64Cipher());
    ciphers.put(AES_ALGORITHM, aesCipher);
  }

  public boolean isEncrypted(String value) {
    return value.indexOf('{') == 0 && value.indexOf('}') > 1;
  }

  public String decrypt(String encryptedText) {
    Matcher matcher = ENCRYPTED_PATTERN.matcher(encryptedText);
    if (matcher.matches()) {
      Cipher cipher = ciphers.get(matcher.group(1).toLowerCase(Locale.ENGLISH));
      if (cipher != null) {
        return cipher.decrypt(matcher.group(2));
      }
    }
    return encryptedText;
  }

}
